Generation of steam and other vapors



Oct. 13, 1931. w. D. LA MONT 1,827,244

GENERATION 0F STEAM AND OTHER VAPORS Filed June 1926 8 Sheets-Sheet 1 INVEN TOR 14 75/? 001/6145 ln/fa/vr BWJW A TTORNEYJ Oct. 13, 1931.

W. D. LA MONT F GENERATION OF STEAM AND OTHER VAPORS Filed June 16,192?.

8 Sheets-Sheet 2 Fifi) IN VENTOR WALTER 001/6145 ZA/Va/vr A TTORNEYJOct. 13, 1931. w. D. LA MONT 1,827,244

GENERATION OF STEAM AND OTHER VAPORS Filed June 16, 1926 S'Sheets-Sheet3 A TTORNEKI Oct. 13, 1931. v w. D. LA MONT 1,327,244

GENERATION OF STEAM AND OTHER VAPORS Filed June 16, 1926 8 Sheets-Sheet4 FEED IN VEN TOR ML 75/2 00 061/45 1/1/70 A TTORNEYJ Oct. 13, 1931. w.D. LA MONT 1,827,244

GENERATION 0F STEAM AND OTHER VAPORS File June 16, 1926 8 Sheet-Sheet 5.R.. m VI A TTORNEYJ Oct. 13, 1931.

W. D. LA MONT GENERATION OF STEAM AND OTHER VAPORS Filed June 16, 1926 8Sheets-Sheet 6 IN VEN TOR WALTER fiauams MMo/vr BYW 5M A TTORNEYJ Oct.13, 1931.

Filed June 16, 1926 8 Sheets-Sheet 7 I-T I INVENTOR A TTORNEYJ Oct. 13,1931. w. D. LA MONT 1,827,244

GENERATION OF STEAM AND OTHER VAPORS le n 1926 8 Sheets-Sheet 8ATTORNEYJ Patented a. 1a, 1931 1,827,244

IDA-150M, OF LARCHMONT, NEW YORK, ASSIGNOB '1'0 LA. PORTION, ACORPORATION OF NEW YQBK WALTER DOUGLAS MONT COB- GENERATIOH 0F STEAK ANDOTHER VAPOIRS Applicatio n fled June 18, Serial No. 116,805.

This invention relates to methods andapmethods and apparatus forgenerating steam [f in water wall boilers boilers.

In the following more detailed descriptions of the present inventionmethods of generating steam andapparatus for steam o generation will bedescribed but it should be understood that the invention whileparticularly suitable for steam generation, is not limited thereto andcan be applied with suitable changes where necessary to the generationof any other vapor from a liquid and accordingly the description shouldnot be considered as limiting the invention in any way to the generationof steam only.

A rapid circulation of water in steam generators and particularly inwater wall boilers and similar radiant heat steam generators is verynecessary in order to effect eflicient steam generation. A rapid and,thorough circulation of water can be efi'ected by means of pumps, asdescribed in connection with water wall boilers in my copendingapplication, Serial No. 77,816, filed December 26,

For some installations it is desirable to eliminate pumps and othermechanically driven moving parts. This is particularly true where asuitable source of power for pumps is not available as, for example,when low pressure steam is generated which is not particularly adaptedfor driving small pumps, or Where the suitable power is available suchas electricity, but is not reliable and is subject to break-down. Inniost installaor similar radiant heat pumps is not serious, as a more orless constant supervision is available, but in some other installations,for example, in certain steam plants for heating buildings the boilersare fired at intervals and the supervision is not constant. It is anobject, therefore,-of the present invention to produce vigorous andreliable circulation without the use of pumps or other mechanicalcirculating devices containing moving parts.

tions, of course, the possibility of failure of,

It is one of the objects of the present invention to bring abouteffective circulation in steam generators and especially in water wallboilers, without the use of any pumps or other devices involvingpositively driven moving parts. It is a further object of the presentinvention-t0 bring about effective circulation without the use ofcomplicated automatic or semiautomatic controls, such as water levelcontrols and the like, or with a minimum of such controls.

According to the present invention relatively small vertical or inclinedgenerating tubes are used and a relatively free return circulationpreferably outside of the furnace or in a relatively cool zone isprovided, The water in the small generating tubes is rapid- 1y heatedand the steam enerated, especially at the lower portions of t egenerating tubes,

rises rapidly, carrying with it the water in the tubes, and in the caseof long tubes which are strongly heated at their lower ends, the water,which is at a pressure greater than the steam' pressure in the boilersteam space, may be sufficiently superheated with respect to the steamtemperature so that in rising through the tubes more steam is generatedas the pressure falls and steam and water are forcibly ejected from thetop of the generating tubes in spurts, the action being very similar tothat of a geyser and resembling in some respects the well known coffeepercolators. The water or mixture of steam and water in the generatingtubes is, of course, of lower s ecific gravity than the water in thedown-tafie tubes or passages which are situated in a relatively coolzone. There will, accordingly, be in most cases a considerabledifi'erence in hydraulic head due to the difference in specific gravityof the fluids in the generatin tubes and the downtake tubes andcirculatlon will be efi'ected by this difierence inspecific gravity.

Another important factor in circulation consists in the velocityacquired by the rising steam bubbles and which tends to bring about veryrapid circulation. In general, circulation is usually due to a number offactors, such as difference in specific gravity and -circulation.

It is possible to restrict the flow into the generating tubes eitherbythrottling or by a lowering of head in the down-take tubes to such anextent that a very large portion' of the water in the generating tubesis turned into steam and comparatively little water is dischargedfrom'the upper portion of the enerating tubes. This system issatisfactory for some water wall boilers, particularly where it isnotnecessary to provide for any considerable steam reserve. For generatorswhich are to be used as primary generators and not as water walls inconjunction with secondary generators, I prefer to keep sufficient waterin the generating tubes either by an unrestricted flow from thedown-take tubes or by a sufficient head of water in the down-take tubes,so that a strong geyser action takes place and a considerable amount ofwater is circulated through the generating tubes. In this mannerfluctuations in combustion temperature and steam use can be more easilytaken care ofthan in installations where the generating tubes containbut little excess water and where there is considerable tendency toevaporate all of the water in the generating tubes when sudden increasesin fire take place. It should be understood, therefore, that in thepreferred embodiments of the present invention, especially in thoseembodiments which are intended to be used as primary steam generators, Iprefer to arrange the units so as to assure the presence of aconsiderable amount of water in the generating tubes at all times andproduce vigorous geyser action. In its broader aspects, however,especially in connection with water wall boilers, the invention is notlimited to this circulation adjustment and also includes generators andparticularly water wall boilers in which the amount of water in theenerating tubes is materially restricted and the tubes may even operateas semi-flash generators.

The geyser action which I utilize in the preferred embodiments of thepresent invention may, in some cases, particularly when the generator isstarted, become undesirably violent and may even, in some cases, tend toreverse the water'fiow. In order to prevent momentary reversals of waterflow it is frequently desirable to provide suitable check valves eitherin the down-take pipes themtake pipes and the generating tubes. The

invention is, of course, not limited to the use of check valves but theyare advantageous in man cases and constitute one of the more speclficfeatures of the invention in its preferred embodiments.

The generating tubes may be connected with steam and water drums, eitherabove or below the water level but where restricted flow is used it isusually desirable to discharge the steam and water above the water levelof the drum, using, if desired, suitable steam separating means. Evenwhere strong geyser action takes place it is frequently advantageous todischarge above the water level, although it is not strictly necessaryin such a case since the geyser action will effect circulation even whenthe dischargeof steam and water is considerably below the water level ofthe upper drum and in some cases this arrangement may be desirable,although in general we prefer to discharge steam and water at or abovethe water level, as there is less tendency for the geyser action to setup water hammers which may, in some cases, set up strains in theapparatus. A better separation of steam and water is also obtainedthereby. Discharging above the water level also makes it possible toplace the water and steam drum at a considerable elevation above the topof the heated portion of the generating tubes and thus obtain a verylarge water head in the down-take pipes with a resulting rapid watercirculation which is very desirable in many cases, especially where thegenerator is intended to be operated at high ratings.

A further advantage of discharging the.

water and steam from the generating-tubes in the fact that by this meansit is possible to place the drum in any suitable location without regardto the shape of the heating furnace. For example, in cases where ageyser tube generator is to be incorporated into an existing furnace,either as a water wall or as an auxiliary generator, the furnace heightavailable, particularly in the case of water wall installations, my notbe sufliciently great to provide for long geyser tubes which arenecessary to bring about the best and mostvigorous circulation. When thetubes discharge above the water level in the upper drum it is possibleto utilize long tubes, only a port-ion of which are subjected to heat,and the principles of the present invention may therefore be applied tomany existing boiler installations without rebuilding or redesigning thefurnace. The same flexibility is frequently desirable even in newinstallations where space requirements are such as to render a tallfurnace structure undesirable- It is also advantageous to dischargeabove the water level where a water wall embodying the features of thepresent invention is in connection with a secondary boiler or boilersusing a common circulation. Such combinations, some of which areillustrated in the drawings, are very effective, as the advan= tages ofthe water wall boiler can be obtained without decreasing the efliciencyof the secondary boiler and even with a considerable increase inefliciency in the case of series cir--v culation which may be arrangedto promote the circulation in the secondary boiler and correspondinglytoincrease its reliability and efiiciencyand it is one ofthe advantagesof the present invention that such combined installations may be'made.

In the general discussion a steam and water drum and down-take pipeshave been referred to. It should be understood,tof course, that theinvention is not confined to installations in which a single drum or aplurality of down-take pipes are used. On the contrary, a plurality ofdrums may be used and a single large down-take pipe or a plurality ofdowntake pipes with or without headers or manifolds may be provided andin this respect the invention is capable of a large number ofmodifications which may be desirable in adapting the principles of theinvention to any particular furnace or boiler and the proper design andplacement of steam and water drums and down-take pipes will, of course,be clear to a skilled steam engineer.

It is one of the features-of the present invention that the generatingtubes are relatively long as compared with their diameter, as thispermits effective geyser action and also promotes elficiency of heattransfer. The invention is, however, not limited to any particularlength, although in general, as pointed out, above longer tubes givebetter results within the limits of practical installations. In somecases, however, particularly in water wall boilers, it may be necessaryto shorten-the tubes for structural reasons,

The shape of the tubes may be varied within wide limits and only a fewof the possible forms will be illustrated in the drawings.

Thus, the tubes may be'in one or more layers, closely or loosely spaced,with or without fins and the like. In the preferred embodiments of myinvention, I prefer to arrange generating tubes in trays connected byheaders having a somewhat similar shape to the trays of generating tubesdescribed in my patent application No. 32,064, filed May 22, 1925, andin the more specific aspects of the invention this constitutes one ofthe advantageous features which reduce expense of installation andparticularly make it possible to change tubes with a minimum of losttime. In its broader aspects of course, the invention is not limited tothe arrangement of tubes in trays and any other suitable arrangement canbe used'and is included within the scope of the invention.

In the preferred modification of my invention, the'steam and water fromthe generating tubes is discharged into a separatingdrum and for mostpurposes, particularly where the amount of water in the generating tubesis considerable and vigorous geyser action takes place, this is the mostadvantageous arrangement. 'It is, however, not the only arrangementpossible .and the steam and water from the generating tubes,particularly when the amount of water is restricted, may be passed intodifferent types of steam separators such as, for example, centrifugal serators or the like, provided with drains eit er to a drum or directly tothe down-take pipes and in some cases it may be desirable to pass thesteam with the entrained water directly to superheaters to generatesuperheated steam. This modification is desirable in some cases whereradiant heat superheaters are used or where superheaters are placed incomparatively hot zones of the furnace as the entrained water serves toprotect the superheater tubes against burning out under varying loadsand at the same time keeps the superheat down to lower figures which arefrequently desirable. Various other combinations are possible and partonly of the water and steam may be discharged directly into one or moresuperheaters in series or in parallel, thus effecting a superheatcontrol particularly when the amount or proportion of the water andsteam ejected from the generating tubes is variable. I do not claim inthe present invention broadly the idea of controlling superheat byinjecting water into the superheater tubes, this forming part of thesubject matter of my co-pending application, Serial No. 83,235, filedJanuary 23, 1926. On the contrary, this feature is claimed in thepresent application only in conjunction with generators embodying themain principles of the present invention. It is an added advantage ofthe present invention in some of its modifications, that part or all ofthe steam and water mixture which is forcibly ejected from thegenerating tubes may be used as a superheat control means.

I have described above and show for the most part in the drawingscertain combinations of water wall boilers. embodying the principles ofthe present invention with steam generators which depend on convectioncirculation and these combinations are particularly advantageous becausethey permit an increase of circulation in boilers of ordinary standardtypes without involving the provision of pumps or other positivecirculating means which necessitate additional moving parts. Theinvention is, however, not limited to water wall boilers combined withsecondary steam generators of the convection type and on the contrary,may bescombined with secondary boilers which are provided with positivewater circulation. I do not,

however, in the present application, include water walls in which thecirculation is in series with boilers having positive circula tion sothat the positive circulation takes place through the water wall as wellas the boiler, as these installations form part of the subject matter ofmy co-pending application, Serial No. 77,816, filed December 26, 1925,referred to above.

The invention will be described more in detailin connection with certainillustrative embodiments which are shown in the drawings. It should beunderstood that these specific examples of boiler installationsembodying the principles of the present invention do not-in any senselimit its scope and, on the contrary, they have been chosen toillustrate in a few examples, as many of the important modifications ofthe present invention as is possible but it will be readily apparent tothe skilled steam engineer that many other modifications andcombinations are possible and will be desirable in certain cases and ingeneral the engineer designing a new installation embodying theprinciples of'the present invention or redesigning an old installation,will adapt the present invention to the particular conditions and needsof the plant in question and the shape and placement of the generatingtubes, together with the other elements of generators and water wallboilers of the present invention will be and must be largely dictated bythe structural conditions of the particular installations in which thepresent invention is to be applied and this is particularly true withregard to water-wall boilers which necessarily must conform in shape andelement placement to the furnace shape and to the room available. Forthis reason the drawings are diagrammatic in nature and the particularforms, sizes and placement of the various apparatus elements will bedetermined by the steam engineer in accordance with the conditions of aparticular installation and in the light of the knowledge and skillpossessed by the art. It is, however, an advantage of the presentinvention that in many cases most or all of the apparatus elements canbe constructed of standard units, which is of considerable importancewhere it is desired to modify existing installations in accordance withthe present invention,

The vigorous circulation in the geyser tubes which is possible with thepresent 111- vention, not only possesses the advantages described above,but also prevents to a large extent the formation of scale since theviolent circulation appears to have a scouring action, scale beingcontinuously removed, and, of course, being readily separated bysuitable screens which may be placed at any desired point in thecirculation. The somewhat high speed of the circulation and particularlythe vigorous turbulence which exists in the principles of the inventionand in which:

Fig. 1 is a vertical cross-section through a steam generator in whichthe generating tubes enter the upper drum belowthe water level;

Fig. 2 is a similar cross-section through a generator in which the tubesenter the upper drum above the water line; 1

Fig. 3 is a cross-section through a modie fied form of generator inwhich the tubes are not exposed to the heated gases throughout theirwhole length;

Fig. 4 is a vertical section through a Wickes boiler with which agenerator of the present invention has been combined in series parallel;

Figs. 5 and 6 are sections through water wall generators designed inaccordance with the present invention, Fig. 5 showing a water level inthe upper steam drums and Fig. 6 a water level below the steam drums;

F 1g. 7 is a diagrammatic plan view of the steam headers shown in Fig.5;

Fig. 8 illustrates water walls of the present invention combined with asingle-pass water tube boiler;

Fig. 9 is a section through a steam generator of the resent inventionassociated with a fire tube oiler;

Fig. 10 is a section through a combined generator and water wall;

Flg. 11 is a section through a Wickes boiler combined with a water wallgenerator according to the present invention;

Figs. 12 and 13 are vertical sections through a modified combination ofgenerators and superheaters; and

Fig. 14 is a Vertical section through the geyser tube generator in whichthe heating gases flow counter to the water and steam circulation.

The drawings are diagrammatic in nature and are not intended to limitthe invention in any way to particular structural details WhlCl'l willvary with the conditions of the installation and it will be clear to askilled steam engineer what particular structural design will be bestsuited to the conditions of any particular plant. It should beunderstood, of course, that steam generators of the present inventionwill be operated with the usual accessories, such as gauges, safetyvalves, water controls, feed controls, blowoifs and the like. In orderto simplify the illustrations, however, in many figures, theseconventional accessories have been omitted, but it should be understoodthat in practical operation, such usual accessories as may be desirablewill be used.

In the construction shown in Figs. 1 and 2, an upper steam drum 1 isconnected w1th a lower drum or header 2 by means of one or more tubes 3of relatively large cross-section. Generating tubes 4 of relativelysmall cross-section connect .the two headers and pass through thefurnace space. In the construction shown in Fig. 1, the generatmg tubesenter the upper steam drum below the water level, whereas in theconstructlon shown in Fig. 2, they discharge above the water level. Insome cases, it may be desirable to cause some of the tubes to dischargeabove and some below the" water level.

, The highly heated gases striking the lower 7 portion of the generatingtubes rapidly heat up the water in these tubes and since the water inthe lower portion of the tubes is under a pressure greater than that inthe upper portion of the tubes, it becomes heated Without formation ofsteam, to a higher temperature than. that which corresponds to steam atthe pressure in the upper reaches of the tubes. As a result, anintermittent geyser action takes place, that is to say, the highlyheated water in the lower portion of the generating tubes proceeds torise and as the pres-' sure drops, steam is generated which tends tocarry the water up with a violent rush, discharging a mixture of steamand water into the steam drum in spurts or pulses. The steam and wateris separated in the steam drum 1 and the excess water circulatesdownwardly through the tubes 3. In many installations, a check valve 5(see Fig. 1), is advantageous as it prevents any tendency to backwardcirculation particularly when the generator first starts. The checkvalve is shown only in Fig. 1, but, of course, it can be applied equallyto the construction shown in the other figures.

F ced water can be introduced at any desired point and mayadvantageously be introduced either into the upper steam drum or intothe upper portion of the tubes 3 so that the incoming cold Waterincreases the density of water in the tubes 3 and correspondinglyincreases the tendency for the hot water in the generating tubes torise. In some cases, however, it may be desirable to introduce the feedwater into the lower header or drum and the present invention is not tobe considered as limitedto any particular method of introducing feedwater.

The construction in Fig. 3 is similar to that in Figs. 1 and 2 but onlythe lower portion of thegenerating tubes is exposed to the heat of thegases. A somewhat more violent geyser action is thereby produced due tothe fact that there is a greater hydraulic head on the water in thegenerating tubes and for some purposes, this construction presents manyadvanta It is also possible in the construction s own in Fi 3 to locatethe drums at a considerable istance from the actual furnace structureand in some cases,

this relatively smaller and shorter furnace structure is of advantage.The operation of the generator is, of course, the same as in the 4, 5,9, 11 and 13, the circulation of generators of the present invention isused to improve the circulation of ordinary boilers. The generatin tubeswhich for convenience will be referre to hereafter as geyser tubes maybe connected to the common type of boiler in many ways. Thus, forexample, the circulation may be in series or series parallel orcombinations of the two. The particular arrangement will be determinedby the design of the common type boiler and will be influenced by thenature of circulation in the common boiler, by the space and shape offurnace and by other structural conditions. The invention should,therefore, in no sense be considered as limited to the combinations withthe particular types of conventional wardly through the tubes 9.Accordingly,

the lower header 6 of the geyser tubes is connected to the portion ofthe drum 7 adjacent to the discharge openings of the tubes 10, whereasthe upper ends of the geyser tubes are introduced into the upper drumabove the discharge of the tubes 9 and in the drawings are shown asdischarging partly above, partly below and partly at the water level.The tubes may, however, be arranged to discharge all above, at or belowthe water level, wherever desired.

The hottest gases from the furnace passing below the arch 12, strikefirst the lower ends of the geyser tubes and heat up the water in thesetubes to a very high temperature,

producing an intense geyser circulation, taking water from the drumbelow the dlscharge of the tubes 10 and discharging the water mixed withsteam at a high rate of speed into the upper drum in the direction ofthe flow .of water from the front to rear of the drum,

drums and tubes exposed to the radiant and convection heat of thefurnace. The connections between the upper drums of Fig. 5 are shownschematically in Fig. 7 I

In the construction shown in Fig. 5, geyser tubes 4 are embedded in thefurnace linm 24 and connect the lower headers 2 with the steam drums 1,return circulation bein through the tube 3 to which is connected thefeed pipe 25 provided with a valve 26 actuated by the water levelcontrol 27. Steam drums 1 are connected to the tube 3 by the pipes 28and 29 and the T connections 30 and 31, which latter enter the drumsbelow the water level. In a similar manner, the steam spaces areconnected by means of the T connections 32 and 33 and the pipe 34 to asteam separator 35, whence the steam passes out through a steam main 36.Water carried along by the steam and separated out in the separator isreturned to the lower header 2 through the pipe 37. The operation of thetubes 44 and feed tubes 43. The steam water wall is the same as thatdescribed in Figures 1 to 3.

In the water wall shown in Fig. 6, the water level is carried below thesteam drums 1 and these latter are provided with separator baffles 38.The arrangment of steam separator 35 and return pipe 37 is similar tothat shown in Fig. 5 and the operation of the water wall is the sameexcept that the geyser action is somewhat less violent as the tubesdischarge above the water and there is, therefore, less resistance tothe surges in the geyser tubes than is the case where they dischargebelow the water level andwhere the mixture of steam and water dischargedmust displace a corresponding amount ofwater.

In Fig. 8, two water walls are associated with asinglepassEdgemoor watertube boiler. The boiler consists in steam drum 41, lower drum 42, waterfeed drum 40, generating spaces of the drums 40 and 41 are connected bythe pipe 45 and the water spaces by the pipe 46. A superheater 47 isprovided connected to the steam spaces of the drum 40 by the pipe 48 anda water preheater 49 is also provided.

The front water wall, consisting of steam drum 1, lower header 2 andembedded geyser tubes 4, is connected to the drum 42 by the feed pipe 50and the drum 1 is connected to the water space in the drum 40 bythe'pipe 51. The steam spaces of the drums 1 and 40 are connected by thepipes 52 and 53, which latter is provided with a valve 54. A separatewater wall steam main 55 is connected to the tube 52 and is providedwith a valve 56. The circulation of the front water wall is partly inseries and partly in parallel with the circulation through the Edgemoorboiler.

A rear water wall consisting of a steam drum 61, a lower header 62,geyser tubes 64, and return tube 63, forms a complete independentcircuit, the steam and water discharged from the tubes 64 beingseparated in the drum 61 with the aid of the bafile 57 g and passing outthrough the steam main 58 Which connects with the pipe 55. Feed g wateris introduced from the drum 42 of the Edgemoor boiler through the pipe59 controlled by the valve 60 which is in turn actuated by the waterlevel control 65. The circulation through the rear water wall is,therefore, independent of the Edgemoor boiler, but feed water is takenfromthe latter and the amount of feed is regulated by the water level inthe drum 61 which in turn varies with the amount of steam generated inthe tubes 64. Thus, one of the water walls operates in series parallelwith the Edgemoor boiler, whereas the other possesses an independentcircuit. Steam from the two water walls can be used separately byclosing the valve 54 and opening the valve 56 and steam can be passedthrough the superheater 47 by opening the valve 54 and closing the valve56.

In Fig. 9, an ordinary fire tube boiler is shown consisting in a shell66, provided with fire tubes 67 and legs 68. A geyser tube generatorconsisting in lower header 69. upper drum 70 and geyser tubes 75 ismounted in the fire tube boiler so that the geyser tubes pass upwardlythrough the fire tubes. The header 69 is connected to the legs 68through the pipes 76 and the drum 70 is similarly connected to the steamspace of the fire tube boiler by the pipe 77. A steam pipe 78 pro videdwith a valve 79 also extends from the drum 70 in order to draw oflsteam. A baflie 80 is also advantageously provided in the drum 7 O andaids in the separation of steam and water.

The circulation of the geyser tube generator is in series with that ofthe fire tube boiler and greatly improves thecirculation in the latter.At the same time, the geyser tubes passing through the fire tubesdecrease the hydraulic mean depth and increase the gas velocity throughthe fire tubes, factors which very greatly increase the heat transferefiiciency. This modification of the present invention as is readilapparent, can be simply and easily applled to a vertical fire tubeboiler without necessitating any radical rebuilding. .A greatlyincreased steamin capacity is thereby obtained due to the additionalheating surface of the ge ser tubes and to the improved circulation inthe fire tube boiler and the increased heat transfer from the heatinggases. Vertical fire tube boilers, despite the fact that they are veryeconomical in construction particularly in small sizes, are ratherineflieient from the standpoint of steaming capacity and for manypurposes are today obsolete or obsolescent. When combined with thegeyser tube generator of the resent invention, however, their steaming eciency is greatly increased and in many cases, this makes it possible toutilize an old firetube boiler which would otherwise have to be scrappedowing to its insufiicient steaming ca acity. It is an advantage of thepresent invention when combined with ordinary types of boilers that manyobsolescent boilers which, however, are

still in good working condition, can be redesigned and brought to asatisfactory state of efli'ciency with comparatively little cost by asuitable combination with geyser tube generators. Such obsolescentboilers represent a very large capital investment in many cases and theflexibility of application of the present invention which enables manyof these older units to be brought toa state of efiiciency satisfactoryfor modern conditions, is of great economic importance.

Geyser tube generators operate most efliciently with long, smalldiameter generating tubes and due to the fact that length of tubemeans'incr'eased efficiency, a very simple and effective combinedgenerator and water wall can be built embodying the principles of thepresent invention. Such a combination is shown diagrammatically in Fig.10. the steam drum 81 and the lower header 82 being,

connected by the circulating tube 83 and by the geyser tubes 84 which,in their lower reaches shown in the drawings at 85, act as a water wall,absorbing the radiant heat from the flame 86, and protecting the furnacewall. In their upper reaches, however, the tubes are ordinary convectionheated generator tubes. The drum 81 is, of course, provided with asuitable steam pipe 86 and may advantageously be provided with a bafile87 in a manner similar to that shown in the foregoing figures.

The lower reaches 85 of the geyser tubes are exposed to. the radiantheat of the furnace and are very highly heated which promotes vigorousgeyser action, since as has been ointed out in the general descriptionof the 1nvention, vigorous geyser action is aided by for the sake ofclearness, but it should be understood that in an actual enerator, avery lar number of tubes will used in order to a stract a maximum ofheat from the gases. It should also be understood that there is no sharpdividing line between the portion of the tubes acting as water walls andthose acting as ordinary generating tubes heated by convection. As amatter of fact, even in their lowest reaches, the tubes are heated to acertain extent by convection and as they extend up through the furnacepass and are bent out to fill the pass, they are more and more heated byconvection and less and less by radiant heat, but there usually is nosudden line of demarcation, although in some installations it may bedesirable toprovide for rather sudden bends, making for a more definiteline of demarcation. The particular arrangement of the tubes will, ofcourse, be controlled by the conditions encountered in any giveninstallation and various aids to effective screening such as fins on thelower reaches of the tubes and the like may be employed. In fact, tubestructures, which have proven advantageous in conventional types ofwater walls, may be applied for the most part to geyser tubes of thepresent invention with such modifications as may be necessary.Obviously, also, the water wall tubes may be partly or wholly embeddedin the furnace wall or two layers of tubes may be provided, one embeddedand the other directly exposed to the fire, or both embedded, or bothdirectly exposed to the flame. Other modifications may also be utilized.I

Fig. 11 illustrates a somewhat diflerent application of the geyserprinciples of the present invention. In the generators which have beenillustrated hitherto, the production of Water at a temperature higherthan that corresponding to the boiling point under steam pressureconditions in the generator has been effected by applying intense heatto the bottom of small generating tubes under a considerable hydraulichead. In other words, the geyser has been formed by heat, waterand'pressure conditions in the generator itself. For many purposes andparticularly where a new unit is to be constructed, this constitutes themost eflicient and economical design. It is not, however. the onlymethod whereby geyser action can be brought about and the essentialconditions of the highly heated water volume at the botby introducingwater at high temperature and under high pressure into the bottom ofthese genera-ting tubes from an external source. This is of greatimportance in connection with certain conventional type boilers whichshow a rather poor steaming capacity owing to sluggish circulation,large tubes and the like. One modification of this idea .is shown inFig. 11 in connection with a \Vickes boiler, a type of boiler which isnot highly efiicient from the standpoint of steam capacity per squarefoot of: heating surface and which can be very easily redesigned toproduce a vigorous and ell'ective geyser circulation.

In the drawings, the \Vickes boiler with the conventional upper drum 88,lower drum 89. front tubes 90, rear tubes 91 and bafile 92. is connectedto a geyser tube generator having a steam drum 1, lower header 2,circulating tube 3 and geyser tubes 4, by means ot'a pipe 93 connectingto the pipe 3 of the geyser tube generator,and extending into the drum'89 and provided with nozzles 94 discharging into the tubes 90. Theauxiliary geyser tube generator, which of course, can be of very muchsmaller size than the Wickes boiler, is shown as a radiant heat waterwall. This is a very effective method of mounting the generator withcertain furnace structures, but of course. any other arrangement can beprovided or the geyser tube generator may be separately fired.

The geyser tube generator is operated at a steam pressure which may beslightly or greatly in excess of that in the Wickes boiler plusthehydraulic head between the drums 88 and 89. The water in the geysertube generato-r is discharged into the steam drum 1 at a highertemperature and under a higher pressure than is the water at the bottomof the tubes 90 in the \Vickes boiler. Accordingly, water will flowthrough the pipe..93 and will be ejected through the nozzles 94 in theform of jets. A reduction of pressure :1 takes place in passing throughthe nozzles 94 and a corresponding formation of steam results since thetemperature of the water is above the boiling point at the reducedpressure. The powerful jet of water and particularly the immediatelyresulting generation of steam causes a vigorous geyser action to takeplace in the tubes 90 and a Very rapid and vigorous circulation takesplace throughout the \Vickes boiler, resulting in a largely increasedsteaming capacity.

The teed to the auxiliary generator is determined by the adjustment ofthe feed valve 95 which is controlled by the water level control 96. Asteam pipe 97 extends from the steam drum 1 to the steam line 98provided with valves 99 and 100 and connecting beyond the valve 100 witha steam line from theVVickes boiler 101. If it is desired to utilize thehigh pressure steam from the auxiliary generator separately, the Valve100 is closed, and the valve 99 is opened. Where, however, the auxiliarygenerator operates at a pressure only slightly above that of the mainl/Vickes boiler, it may be desired to mix the steam from this generatorwith the steam from the Wickes boiler and this can be efi'ected byshutting the valve 99 and by opening the valve 100, the opening of thevalve being just sufficient to cause a pressure drop or throttlingeffect ,to take place, the drop being great enough to equal theditferen-ce in pressure between the auxiliary generator and the W ickesboiler.

The amount of water which is introduced through the pipe 93 should besufficient to cause vigorous geyser action in the Wickes boiler and neednot be greater than this amount, although, if desired, it may be largelyincreased up to the amount represented by the steam taken off from theWickes boiler. This naturally constitutes an upper limit to the amountof water which can be fed in. A suitable regulation of feed can beeffected by operation of a valve 102 in the pipe 93 and controlled bythe water level control 103 on the Wickes boiler, thus preventing theintroduction of an amount of water in excess of that evaporated in theWickes boiler. Manual control of the valve 102 can, of course, beutilized. Additional feed can be introduced into the Wickes boilerthrough the feed pipe illustrated which is controlled by the valve 196.This additional feed is necessary when the amount of water introducedfrom the geyser tube generator into the Wickes boiler is less than theamount of steam evaporated in the latter. The valve 196 may becontrolled manually or it may be hooked u to the water level control 103as shown. y providing valve 196 with a dash pot of ordinary constructionit will open in any desired relation with the opening of the valve 102.Thus, for example, the control may be arranged so that valve 196 willnot begin to open until valve 192 has been fully opened or any othersuitable regulation which will determine the proportion of hot waterfrom the geyser tube generator and cold feed water introduced into theWickes boiler may be utilized.

The geyser action of the present invention can be very effectivelycombined with a control of superheat which is of considerable importanceWhere a very even superheat temperature is required and which may alsobe utilized in order to protect superheaters in very hot zones of thefurnace. Two modifications of this method-of superheat control are shownin Figs. 12 and 13.

In the construction shown in Fig. 12 two geyser tube generators areillustrated with steam drums 126 and 130, lower headers 127 and 131,return circulation pipes 128 and'132 and geyser tubes 129 and 133. Asuperheater is associated with each generator, the superiob superheaterassociated with geyser tubes 129 is provided with an up ier header 143,a lower header 144 and super ieater tubes 134. the lower header 144 ofthis latter superheater ing connected to the superheated steam main 140.A ipe 139 joins the lower header 142 to upper eader 143. A pipe 136connects the steam spaces of the drums 126 and and pipes 137 and 138convey the steam from both generators to the upper header 141 of thesuperheater associated with the geyser tubes 133. Thence, the steampasses down through the superheater tubes into the lower header 142,then through the pipe 139 into the upper header 143 of the othersuperheater, down through the second set of superheating tubes 134 intothe lower header 144 and thence out through the superheated steam mainwhich main is provided with a thermostat 155.

T connections 145 are placed in some or all of the geyser tubes 129 andsteam and water pass through the tube 146 and valve 147 into thesuperheater header 143. A similar set of "PS 148 are mounted in thegeyser tubes 133 and are connected to the header 141 by the pipe 149 andvalve 150. The valves-147 and 150 are respectively operated by thediaphragm chambers 151 and 152' through the rods 153 and 154. Thethermostat 155 connects with the diaphragm chambers 151 and 152 throughthe pipe 186.

In 0 oration, saturated steam at substantially t e same pressure isgenerated in the two geyser tube generators and passes in series throughthe superheaters, first through the tubes 135 and then through the tubes134, being superheated and passing oil through the superheated steammain 140. When the temperature of the superheated steam rises too high,the thermostat 155 actuates the diaphragms 151 and 152 and opens thevalves 147 and 150, permitting a portion of the mixture of saturatedsteam and water in the geyser tubes 129 and 133 to flow into thesuperheaters, thus cooling down the superheated steam and preventingburning out of the superheaters. The openings of the valves 147 and 150can, of course, be varied so that the proportion of saturated steam andwater entering the superheater tubes 134 and 135 may be the same ordifi'erent, depending on the safety requirements for the differentsuperheaters and on the extent of heating surfaces and other factors.

The generators in Fig. 12 are shown as separate from each other, butthis is in no sense essential to the invention, and on the contrary, thehot gases may advantageously in many cases be caused to circulate inpara lel through the generators and the proportion 01? heat on thedifferent generators can be varied. Thus, for example, a more vig" orousheating of the tubes 134 is desirable in some cases in order to producehigh superheats, as the hottest gases then come in contact with thesteam which has already been superheated or dried in its passage throughthe superheater tubes 135 of the first superheater and a continuedadequate heat head is provided which results in effective heat transer.g The introduction of water into the superheaters and the parallelplacement of generating tubes and super-heating tubes are not claimedbroadly in this application, but form a part of the subject matter of myapplication Serial N 0. 83,235, filed January 23, 1926. In the presentapplication, these features are claimed only in combination with geysertube generators which form the broad subject matter of the presentinvention.

In Fig. 13'two geyser tube generators and associated superheaters areshown arranged for series circulation of heating gases. The lower geysertube generator consisting in steam drum 156, lower header 157,circulating tubes 158, geyser tubes 159 and superheater tubes 160, isplaced in the lower portion of the furnace and contacts with the heatinggases directly from the source of combustion. This generator andsuperheater may, there- Ii;0re, be operated in part at least by radianteat.

The upper generator having a steam drum 161, lower header 162,circulating pipe 163, geyser tubes 164 and superheater tubes 65 isarranged in the-stack and contacts with heating gases which have alreadypassed over the generating and superheating tubes of the lowergenerator.- The superheaters are, of course, provided with the usualheaders 166 and '167 for the tubes and headers 168 and 169 for the tubes165. A pipe 170 provided with a valve 171, permits introduction of amixture of steam and water from the geyser tubes 159 into thesuperheater header 166 and a similar pipe 172 provided with a valve 173permits introduction of steam and water from the geyser tubes 164 intothe superheater header 168. The steam spaces of the drums 156 and 161are connected to a common saturated steam main 174 provided with a valve175 by means of the pipes 176 and 177. A pipe 178 provided with a valve179 leads from the pipe 176 to the superheater header 166 associatedwith the lower generator and a similar pipe 180 provided with a valve181 connects the pipe 176 to the super heater header 168 and also formspart of the passageway through which steam and water can be introducedinto the header from the geyser tubes 164. The lower superheater headers167 and 169 are connected to pipes 182 and 183, respectively, whichpipes unite to form the superheated steam main 18a 5m.

vided with a valve 185.

In operation, saturated steam is generated in both of the generators andpart or all of it can be used'as such by an opening or closing of thevalve 175. In the usual case, however, where it is desired to superheatthe steam, the valve 175 is closed and the valves 179 and 181 are 0ened, causing the steam to pass in parallel t rough the twosuperheaters. By a suitable operation of the valves 179 and 181, theproportion of the steam passing through different superheaters may bevaried, which provides for a control of the superheat such as isdescribed in my co-pendin application, Serial No. 83,235, referred to aove. Where a still further control of superheat is desired,

and particularly where it is advisable to pro-.

tect the superheater tubes water and steam from the geyser tubes can beintroduced into the superheater tubes through the pipes 170 and 172 by asuitable opening of t e valves 171 and 173. The amount of introductioncan be so varied as to produce superheated steam of the same temperaturein both superheaters. This will necessitate, of course, in most cases,the introduction of more water into the superheater tubes 160 than isnecessary in the case of the tubes'165 owlng to the fact that the formerare situated in a very much hotter zone and in the embodimentillustrated in Fig. 13 are also ex osed to a considerable amount ofradiant eat, although being somewhat shielded by the generating tubes159. It is by no means necessary, however, to generate superheated steamof the same quality in both superheaters and, on the contrary, suerheated steam of varying temperatures an quantities can be produced inthe different superheaters and by mixing in the superheated steam main184 superheated steam of the desired quantity and temperature can beproduced.

When the generators are first started, it may be necessary to protectthe superheater tubes and particularly the superheater tubes 1160 whichare exposed to the full heat of the flame. In order to protect thesetubes, the valve 171 may be opened, the valve 185 closed .-and the valve181 opened. The water passing through the pipe 170 is transformed intosaturated steam in the superheater tubes 160, thus protecting them fromburning out and the saturated steam thus produced passes upwardlythrough the pipes 182 and 183 and up through the superheater tubes 165where it is superheated and finally joins the saturated steam pipe'176.If it is desired .to produce saturated steam only or steam havlng butslight superheat, this same arrangement can be utilized so that thesuperheated steam passing from the pipe 180 mixes with the saturatedsteam in the pipe 176 and joining the saturated steam in the pipe 177,passes out through the saturated steam main 174;, the

team

valve 175,0f course, having been opened. By this means, the highsteaming capacity of the superheater tubes 160 can be utilized and the.superheat imparted to this portion of the steam b the superheater tubes165 can be effective y used to dry the saturated steam generated andassure good quality.

The broad idea of controlling the temperature of the superheated steamby passing saturated steam in parallel through two superheaters situatedin difierent heatzones and regulating the proportions of steam passingthrough the different superheaters is not claimed broadly in the presentapplication but forms part of the subject matter of my co-pendingapplication, Serial No. 83,235. In the present application, this featureis claimed only in combination with the particular method of injectingwater and with the geyser tube generators of the present invention.

Figs. 12 and 13 illustrate series or parallel arrangements ofsuperheaters with manual or automatic control of water injection.Obviously, either method of control can be associatedwith eitherarrangement and series or parallel arrangement of superheaters can beassociated with series or parallel flow of the heating gases over thegenerating tubes and superheaters or with independently firedgenerators. Other combinations are possible and will be utilized bythose skilled in the art wherever the conditions of individualinstallations render it desirable.

In Figs. 12 and 13, the only steam passing through the superheaters isthat generated in the geyser tube generators themselves. The advantagesof superheat regulation by in ect1on of the mixture of steam and waterfrom I geyser tubes is, however, not confined to super eaters in whichall of the steam is taken from the geyser tube generators themselves. 0nthe contrary, where geyser tube generators are associated with othersources of steam the superheaters may be fed from these other steamsources alone or may take steam, both from the other sources and fromthe geyser tube generators, the temperature in each case beingcontrolled by suitable injection of water and steam from the geyser tubegenerators, as shown in Figures 12 and 13.

Fig. 14 illustrates a modified geyser tube enerator with a reverse flowof heating gases. he generator consists in an upper drum 187, lower drum188, downtake tube 189 and geyser tubes 190. A check valve 191 mayadvantageously be placed in the down-take tube. Heating gases enter thetop of the furnace structure, for example, from a powdered coal burner192 and flow downwardly over the geyser tubes 190 and then upwardly intoa stack 194, the draft of which may advantageously be augmented by theblower 193. Other sources of hot gases may be used instead'of a powderedcoal burner such as, for

- sary to superheat the water in the lower reaches of the geyser tubescare must be taken to provide for a vigorous circulation, as otherwisethere is danger that the upper reaches of the tubes may be burnt outbefore geyser action takes place. The same reason makes it desirable touse relatively small tubes containing comparatively small amounts ofwater in their lower reaches, so that a comparatively short heatingeriod is suflicient to superheat the water an geyser action sets inalmost at once.

What is claimed as new is:

1. Apparatus for the generation of steam and other vapors comprising incombination relatively long generating tubes exposed to heat throughouttheir lower reaches at least, and means including a conduit forproviding a path of unrestricted return flow and for maintaining a waterlevel in the generator so located as continuously to provide a head ofwater above said lower reaches at such a hei ht that the water withinthe tubes in sai lower reaches is subjected to pressure considerablyabove that corresponding to the temperature of the steam generated anddischarged from the tubes, the amount of water maintained in the tubes,the proportions of the tubes in relation to the capacity of said conduitand their relation to the heat source being such that a relatively highvelocity is produced therein and the reduction 1n pressure of the wateras it rises in the'tubes causes vigorous geyser action therein.

2. An apparatus according'to claim 1 in which generating tubes areunheated for a considerable proportion of their length in their upperreaches, in which upper portions the reduction of pressure isprincipally effective to produce the water clrculating geyser action. I

3.. Apparatus for generating steam according to claim 1 in which thegenerating tubes are exposed to radiant heat.

4. A steam generator comprising a steam generating tube ofrelativelysmall diameter arranged with one end at a relatively greatdistance above the other end, a chamber adj acent the upper end of thetube for separating from the steam any water discharged from the tubetherewith and a conduit. of relatively large diameter as com ared withthe diameter of the generating tu e and connecting the chamber with thelower end of the generating tube and constructed to provide a freereturn flew to said lower end of the water separated in the chamber,whereby the water within the lower reaches of the tube is subjected to apressure sufiiciently in excess of the steam pressure in the chamber tocause it to be superheated above the temperature of the steam so that insaid lower reaches of the tube ebullition is repressed and in the upperreaches violent geyser action is brought about for discharging anyexcess water into the chamber and an effective circulation in the systemis produced.

5. Steam generator according to claim 4 in which the superheating of thewater in the lower reaches of the tube is eflected by subjecting theselower reaches to the intense heat of radiation of the source of heat ina furnace While subjecting the upper reaches to the normal gastemperature.

6. Steam generator according to claim 4 in which the steam generatingtubes are arranged as a water wall adjacent the side walls of a furnaceof great height relative to its cross section.

7. A steam generator comprising a steam generating tube of relativelysmall diameter and relatively long length arranged with one end abovethe other, a chamber connected to the upper end of the tube forseparating from the steam generated in the tube any water dischargedfrom the tube therewith, a return conduit of relatively large diameteras comared with the diameter of the tube providing a path for free flowtherethrough and connectin the water space of the chamber with the owerend of the tube, said chamber being located at such a height inconsideration of the length of the tube and its diameter that in thesteam generating process the water in the lower portion thereof issubjected to a pressure sufliciently in excess of the steam pressure inthe chamber to cause the water to become heated appreciably above thetemperature of the steam, whereby in,

the lower portion of the tube ebullition is repressed and in the upperportion of the tube violent geyser action is brought about fordischarging any excess water into the chamber and producing an effectivecirculation in the system.

8. A process of generating steam in a tube having one end higher thanthe other which consists in heating the water contained in the lowerreaches of the tube to a temperature in excess of the temperature of thesteam to be generated, maintaining a water column above said lowerreaches so as to produce a pressure on the Water therein suflicient torepress ebullition, causing the water to move upwardly with highvelocity in the tube while reducing the pressure thereon whereby violentebullition takes place in the upper reaches and causes any excess waterto be discharged with the steam from the upper end of the tube,

separating the steam and water so discharged, and returning the excesswater t0 the lower reaches of the tube by &elivering it to the volume ofwater contained in the Water cqlumn.

Signed at New York, New York, this 15th day of June, 1926. I

' WALTER DUUGLAg LA. MUNT.

meg-mm

